所以我有一个问题。我环顾四周，环顾四周，但没有运气。我想使我的身体背景透明，但使文本不透明。现在，我保持相同的不透明度。这是我的代码：

@charset "utf-8";
body {
    font: 100%/1.4 Verdana, Arial, Helvetica, sans-serif;
    background-color: #42413C;
    margin: 0;
    padding: 0;
    color: #000;
}

/* ~~ Element/tag selectors ~~ */
ul, ol, dl { 
    padding: 0;
    margin: 0;
}
h1, h2, h3, h4, h5, h6, p {
    margin-top: 0;
    padding-right: 15px;
    padding-left: 15px;
    opacity:1;
}
a img { 
    border: none;
}
a:link {
    color: #42413C;
    text-decoration: underline;
}
a:visited {
    color: #6E6C64;
    text-decoration: underline;
}
a:hover, a:active, a:focus {
    text-decoration: none;
}
.container {
    width: 750px;
    margin: 0 auto;
}
.content {
    padding:20px;
    width:710px;
    position:relative;
    background:#CCC;
    opacity: 0.5;
}
.fltrt {
    float: right;
    margin-left: 8px;
}
.fltlft { 
    float: left;
    margin-right: 8px;
}
.clearfloat { 
    clear:both;
    height:0;
    font-size: 1px;
    line-height: 0px;
}
.header {
    top:0%;
    width: 750px;
    height: 200px;
    background-image: url(images/header.png);
    background-repeat:no-repeat;
    background-position:center;
}
.navbar {
    height: 50px;
    width: 750px;
    position: relative;
    z-index: 2;
}
#bg {
    position: fixed;
    top: 25%;
    left: 15%;
    z-index: -1;
}
div {
display: block;
}